Ford Transmission Issues

[PCCN]

Have 2003 Ford Econoline Superduty Van with box on back. The transmission seems to not want to change gears at times, mainly going up hills. Yes, lots of weight on it. It already has a cooler on it. I read an article (thought it was on this board) previously where a couple of other cleaners ran into the same problem and added some type of "attachment" to their transmission to keep it from this problem.

Anyone seen this article or have an idea of resolution short of a rebuild?

 

[Goomer]

Start with the basics.

Fluid level??
Fluid color??
Fluid smell??

Any codes??